Have you ever used nunchaku, Kikkoman?
Swinging it like a baseball bat is a sure way to injure yourself.
The only way that you can keep from hurting yourself with chucks is to catch the opposite end if it misses, and if it connects, to bring it back, using the rope an your side/shoulder to keep from connecting with yourself.
Chucks opporate on similar principles to the midevil flail, except that you can use either end to attack.

Do they allow nunchucks? I want to fight a stick person using nunchucks.

I'm sure someone at a gathering will oblige you. Isn't it always up to the participants what they allow? I don't see a stick/nunchaku fight going much different than a stick/stick fight. I would think the other guy would bring the fight to the inside (or ground) to basically shut down the full potential of the rice flails.